Scroll type fluid machinery is well-known, an example of which is Japanese Patent Publication Gazette No. (Hei 1-35196, filed on Jul. 24, 1989) as shown in FIG. 6.
The scroll type fluid machine shown in FIG. 6 is provided with a first rotary shaft D1, a second rotary shaft D2 having a second rotation axis 02 eccentric to a first rotation axis 01 of the first rotary shaft D1, a first scroll S1 which is provided with a first base P1 and a spiral member R1 erected at the front surface thereof and is rotatable around the first rotation axis 01, a second scroll S2 which is provided with a second base P2 and a second spiral member R2 erected at the front surface thereof and is rotatable around the second rotation axis 02, a motor M of a drive source for driving the first rotary shaft D1, a synchronous mechanism S comprising an Oldham's ring for synchronizing the rotation of the first scroll S1 with that of the second scroll S2, a body casing or housing C having an internal space in which the first and second scrolls S1 and S2 are located. The housing including an upper housing U and a lower housing G, and an open suction port L which is in fluid communication with the interior of the housing C and allows fluid to pass into the internal space and then flow into a compression pocket or volume V, formed between the first spiral member R1 and the second spiral member R2.
The motor M rotates the first scroll S1, and the second scroll S2 is rotated at the synchronous speed with the first scroll S1 following the rotation thereof. Low pressure fluid flowing through the suction port L into the internal space of the body casing C flows through the outer peripheries of the first spiral member R1 and second spiral member R2 into the compression pocket or volume V and is sequentially compressed as it moves toward the center of the first spiral member R1 and second spiral member R2. High pressure fluid, after compression, flows to the exterior through a discharge port E provided in the first rotary shaft D1. An oil tank T is provided below the body casing C, and a discharge port H is located at the side wall of the oil tank T.
In the above-mentioned scroll type fluid machine, the first and second scrolls S1 and S2 rotate together and the fluid in the internal space of the body housing C is subjected to the centrifugal force generated as a result of the rotations of the first and second scrolls S1 and S2, thereby causing it to flow radially outwardly therefrom. Therefore, the fluid is inhibited by the centrifugal force from entering the compression pocket or volume V and the suction pressure at volume V is relatively lower than the pressure at the suction port L, thereby reducing volumetric efficiency of the machinery.
It is an object of the present invention is to provide a scroll type fluid machine which can facilitate entry of fluid into compression volumes, minimize suction pressure reduction, and improve volumetric efficiency.
It is a further object of this invention to increase the volumetric efficiency of a scroll type fluid machine by utilizing the centrifugal forces generated by the rotation of the scrolls, to increase the pressure of fluid entering into the compression pockets or volumes, thereby improving volumetric efficiency.